[Autoimmune cholangitis (AIC) associated with myositis in monozygotic twins].

A 53-year-old female suffered from joint pain and muscle weakness in all extremities in 1991. Laboratory data showed increased creatine phosphokinase (CK) and aldolase. Liver dysfunction and weakness of proximal muscles also appeared and polymyositis (PM) was suspected. Two years later, she was diagnosed with dermatomyositis (DM) through skin and muscle biopsy. Because elevation of biliary enzymes and transaminases were continued, liver biopsy was performed in 1997. Histopathological findings of her liver were compatible with primary biliary cirrhosis (PBC). Similar conditions were noticed in her identical twin as well. DM associated with PBC is unusual and cases of monozygotic twins with both conditions are very rare. The difference between PBC and autoimmune cholangitis (AIC) which has recently reported and the genetic influence on the pathogenesis of DM and AIC are also discussed.